The third relation of the artery in front is the anterior wall of the iliac region ; the details of this it is not proposed to examine at length, but only so far as they may be concerned in the relations of the artery ; the structures com posing the wall being numerous, they may be conveniently arranged into three sets, viz., the superficial, the intermediate, and the deep or lining structures.
The superficial structures are three, the skin, the subcutaneous cellular tissue, and the fascia. Of these the first does not require to be dwelt upon ; the second is subject to much variety in its condition ; it forms a stratum of considerable thickness in every case ; when, however, the superficial cellular stntcture of the body is charged with much adeps, it then forms an uniform and thick stratum of fat without any distinction into lamina ; this is best exemplified at the early periods of life, particularly in children cut oil' by an acute disease ; when, on the contrary, the body is emaciated, it forms a condensed cellular ex pansion much thinner than in the former case, and divisible frequently into lamina. This structure is continued from the iliac over the other regions of the abdomen, downward upon the thigh, and in the middle line upon the spermatic process of the male and the organs of generation. Numerous superficial vessels are contained in and ramify through it ; these are derived from several sources, but that which is proper to the iliac region is the superficial epigastric artery which ascends from the femoral superficial to the aponeurosis of the external oblique muscle and intermediate to the inguinal rings.
Beneath the subcutaneous stratum is the third superficial structure, the fascia ; this is a thin dense expansion by which the external oblique muscle and its aponeurosis are covered ; it is not confined to the abdomen, hut is con tinued into a similar expansion upon the ad joining regions whether upward or downward ; it adheres closely to the muscular portion of the oblique, particularly at the junction of the muscular fibres with the aponeurosis along the linca semilunaris, but its connection to the aponeurosis itself is more free, an extensible and delicate cellular tissue being interposed. Hence it is easily detached from the latter ; it is most dense, fibrous, and strong upon the iliac region ; as it ascends thence it becomes less dense and fibrous, and assumes more of a simply condensed cellular character; it is not equally distinct in every subject, in all it can be recognized at the crural arch, and for some distance above it, but as it recedes from the arch it frequently seems to be gradually re solved and to cease. Below, it is attached posteriorly to the outer edge of the crest of the ilium, and along this line it meets the insertion of the fascia lata of the back of the thigh ; in front between the superior anterior spinous process of the ilium and the spinous process of the pubis it descends over the crural arch, having only a cellular connection to it, and being separable with ease from it, as well as from the aponeurosis of the oblique ; immediately below the arch it is united to the superficial surface of the fascia of the thigh, both externally and internally, on the latter side passing back to the pectineal line of the pubis, into which it is inserted along with the pubic portion of the fascia lata; in the interval between the spinous processes of the pubis it is prolonged down ward upon the spermatic processes, and is continued upon them in the form of a sheath into the scrotum, where it invests the testicle ; it is very thin and transparent upon the spermatic process. The existence of this structure, to
which attention appears to have been first directed by Camper, can always be demon strated however fat or young the subject may be, though, as has been stated, it is not always equally manifest ; it seems distinct from thr: subcutaneous cellular structure,which frequently forms a uniform and thick stratum of fat be tween it and the skin. Different views have been taken of its nature; by Searixt it is re garded as a prolongation of the fascia lata of the thigh, while others and the majority consider it as a continuation of the superficial fascia, so willed, of the same part,and formed by the deep stratum of the abdominal subcutaneous cellular structure converted by condensation or removal of its adeps into an expansion ; to me it appears that the view taken of its nature by Scarpa is cor rect, itt in the sense that it is a prolongation of the fascia lain, but that it is of the same nature, and that it is to the abdomen the same structure which the fascia lata is to the thigh ; it is a question entitled to consideration only for ac curacy's sake, but I have frequently verified the inferior connections of this expansion such as they have been detailed, and further it appears to me that it is not properly continuous with the superficial fascia of the thigh, for if it be detached from the aponeurosis of the oblique muscle and the crural arch without injury to its connection with the fascia lata, and be then held perpendicular to the latter, the superficial fascia of the thigh may be removed from the angle which it will thus form with the fascia lata, and its connection still remain perfect : a favourable subject and a careful dissection will certainly be required for the purpose, but this circumstance will not invalidate the con clusion ; it is also to be recollected in making the dissection, that the fascia detaches processes over the inguinal lymphatic glands.